Monaco owner Dmitry Rybolovlev has been detained in the principality in an investigation into suspected corruption and other allegations.
Lawyer Frank Michel said Rybolovlev, a Russian tycoon, was detained in Monaco on Tuesday.
French newspaper Le Monde, which first reported that Rybolovlev had been detained, said his home had been searched.
Michel is the Monaco lawyer for Swiss art dealer Yves Bouvier, who has lodged a legal complaint for corruption and money laundering that centres on a lawyer for Rybolovlev.
Lawyers for Rybolovlev would not say, when asked on Wednesday, whether Rybolovlev remained in detention. They sent a statement dated Tuesday that said Rybolovlev was being questioned.
The Russian Embassy in Paris, which oversees Monaco, said it was aware of the detention and had asked the Monaco authorities for information but received no response.
Meanwhile, Thierry Henry’s difficult start to life as Monaco manager continued with a 4-0 Champions League defeat at home to Club Brugge, his third defeat in a five-game run without a win.